1. Field of the Invention
The present invention relates generally to display units and input units of computers, and more particularly to an information processing apparatus to be used as a display unit and an input unit of another computer, and an information processing method.
2. Description of the Related Art
In recent years and continuing, equipment with built-in computers is being widely used. For example, there are manufacturing devices of industrial products, examination devices, medical devices, and monitor devices that are connected to a computer with a built-in control unit and controlled by the control unit. Unlike typical computers, some of these devices can operate without being connected to display units such as an LCD (Liquid Crystal Display) or a CRT, or to input units for inputting characters and coordinates such as a keyboard or a mouse.
Such a device is often configured with an OS (Operating System) and application software operating on the OS. For purposes such as data back-up, device maintenance, and software updating, the device needs to be connected to a display unit and an input unit. Otherwise, when the device is performing normal operations, neither the display unit nor the input unit is necessary, and therefore, the device does not need to be connected to the display unit or the input unit. Hence, it is uneconomical in terms of space and cost to have the display unit and the input unit connected to the device under such normal operations.
FIG. 8 is an example of a conventional connection configuration. Under normal operations, an external information processing apparatus 1 does not need to be connected to an external display unit 2, an external keyboard 3, or a mouse 4. The external information processing apparatus 1 has a built-in extended input-output unit (not shown) and controls an object device (not shown).
For purposes such as data back-up, device maintenance, and software updating, the external information processing apparatus 1 may be connected to the external display unit 2, the external keyboard 3, and the mouse 4. Another information processing apparatus 5 may be operated near the external information processing apparatus 1 for transferring the data to be backed up or for storing the software to be updated.
A display unit 6 of the information processing apparatus 5 can be used as the display unit of the external information processing apparatus 1, instead of the external display unit 2. However, the information processing apparatus 5 is only used as a display unit, and therefore, the external keyboard 3 and the mouse 4 also need to be connected to the external information processing apparatus 1. If such peripherals are permanently connected to the external information processing apparatus 1 for purposes such as data back-up, device maintenance, and software updating, additional costs and spaces are required and the total installation area including the external information processing apparatus 1 becomes considerably large.
FIG. 9 is a block diagram of an internal configuration of the conventional information processing apparatus 5 (in this example, a laptop computer). An information processing apparatus control unit 11 (core processing unit) shown in FIG. 9 configures the basic structure of the information processing apparatus 5, including various input output control units such as a CPU, a memory, and a network, a storage unit and a power source unit for supplying power to these units. The information processing apparatus control unit 11 processes information exchanged between input output control units including a display control unit 12, a keyboard control unit 13, and a pointing device control unit 14, by executing a program stored therein. The configuration of the information processing apparatus control unit 11 (core processing unit) is the same in the conventional technology and in an embodiment of the present invention.
The display unit 6 is controlled by the display control unit 12. The display control unit 12 has functions of outputting a display signal to an external display unit output connector 12a, and displaying on the display unit 6 display signals of an external apparatus received via an external display signal input connector 9. Furthermore, the information processing apparatus 5 includes an external keyboard input connector 13b and an external mouse input connector 14b so that the external keyboard 3 and the mouse 4 can be connected and used instead of a keyboard 7 or a pointing device 8 that are built in the information processing apparatus 5. However, the keyboard 7 and the pointing device 8 of the information processing apparatus 5 cannot be used as peripherals of the external information processing apparatus 1.
Other than the above configuration, there is a conventional switching unit widely used in a system where a set of a display unit and an input unit (keyboard/mouse, etc.) is provided for plural computers, and the switching unit switches the object computer for which the set is to be used among the plural computers. The switching unit is useful for one operator to operate plural computers. However, effects of the switching unit cannot be appreciated when only one computer is operated. Furthermore, because the set of the display unit and the input unit is initially provided, it is uneconomical in terms of space and cost when an apparatus does not require a display unit or an input unit under normal operations.
Patent Document 1 discloses a method of displaying display signals from an external computer on a display unit built into another computer. However, the method disclosed in Patent Document 1 is limited to using the built-in display unit as a display unit of the external computer; the computer with the built-in display unit cannot serve as an input unit for another computer.
Patent Document 2 discloses a unit to input display signals of one information processing terminal to be combined with display signals of another information processing terminal and displayed on a display unit of the other information processing terminal. However, the application of the technology disclosed in Patent Document 2 is limited to display units as in the case of Patent Document 1. An input unit needs to be provided for each information processing terminal, which input unit is either connected to or built in the information processing terminal. Therefore, the user needs to take the trouble of operating both input units, which is not necessarily convenient.    Patent Document 1: Japanese Patent No. 3473446    Patent Document 2: Japanese Laid-Open Patent Application No. 2004-163706
Portable computers such as laptop computers have built-in display units and built-in input units such as the keyboard/mouse (pointing device, etc.), and can be conveniently carried wherever the user desires. However, the built-in display unit and the built-in input unit can only serve for the portable computer in which they are installed.